1. Field of the Invention
The present invention relates to a physical property evaluation method for optical fiber coating used in evaluation of a coating material in a coated optical fiber for optical transmission or in product inspection of coated optical fibers produced, and to the coated optical fiber.
2. Related Background Art
A coating of the coated optical fiber affects optical transmission characteristics or lateral pressure characteristics. Therefore, it is necessary to control physical properties, particularly, those of the first coating layer (primary layer).
A well known example of a method for evaluating the shear modulus of elasticity or the tensile modulus of elasticity of the first coating in the coated optical fiber is the one described in International Wire & Cable Symposium Proceedings 1993, p. 864. This evaluation method includes removing a part of the coating in the coated optical fiber, thereby producing a sample with only an optically transparent member or glass portion projecting, imposing a tensile load on the optically transparent member while securing the peripheral portion of the coated optical fiber, thereby causing shear elastic deformation to a material forming the first coating layer, thus measuring a shear modulus of elasticity of the material, and then converting it into a tensile modulus of elasticity.